Drainage Control Plan

A Drainage Control Plan is required for larger projects that must meet all 10 minimum requirements for stormwater management identified in the Pierce County Stormwater Management and Site Development Manual.

 See Volume I, Section 3.3

Application Checklist

The Application Checklist provides the list of individual documents that are required for a complete application for engineering projects.

Site Development Drawings

Site Development Drawings provide specific details, dimensions, and construction standards for a project that show how the property will be modified to accommodate an applicant's proposed development and comply with Pierce County's regulations pertaining to stormwater, grading, vehicle access, roadways, and critical area regulations. 

A professional engineer must prepare Site Development Drawings for a Drainage Control Plan.

 See Volume I, Sections 3.3.2 and 3.3.3

Drainage Report

The Drainage Report is a significant component of a Drainage Control Plan. The report contains the analysis, engineering computations, and soils report information that formulate the basis of the designs that are reflected on the Site Development Drawings.

The Drainage Report includes information on existing site conditions, infiltration rates, soil types, downstream analyses, facility sizing, drainage basin mapping, and floodplain analyses. A professional engineer must prepare the report. 

 See Volume I, Section 3.3.4

Construction SWPPP Narrative

A construction SWPPP Narrative is a report prepared by a professional engineer that addresses how pollution will be controlled during construction of a project. There are 13 elements that need to be considered and addressed.

 See Volume I, Section 3.3.5 and Volume II, Section 2.2.1

Maintenance and Source Control Manual

The Maintenance and Source Control Manual is a document that is prepared by a professional engineer that explains the long term and regular maintenance requirements for a project's stormwater facilities. Source Controls are the application of pollution prevention practices on a developed site that are designed to reduce the contamination of stormwater runoff at its source. Source control measures are specific to the uses of a site. Source control measures provide guidance on how to prevent pollution from a myriad of sources such as swimming pool maintenance or above ground storage tanks.

Pierce County has created a downloadable PDF version of a Maintenance and Source Control Manual that meets the Auditor’s recording standards. The engineer completes the form fields and selects the appropriate checklists and source control measures from the document. 

Included are examples and instructions for preparing the required stormwater system maps. The purpose of the map is to show the project area subject to the agreement and show the stormwater features requiring maintenance. Full-size site plans reduced to letter-size will not meet the MSCM map requirement.

 See Volume I, Section 3.3.6

Establishment of Maintenance Covenant

The Maintenance Covenant for a Drainage Control Plan is a document that is recorded on a parcel that requires a property owner to maintain the stormwater management facilities (catchbasins, ponds, permeable pavement, downspout infiltration trenches, rain gardens, bioretention facilities, etc.) that are constructed on a site. The covenant contains maintenance instructions for each facility type.

 See Volume I, Section 3.3.7